[LTP] [PATCH 1/2] syscalls/pidfd_open01.c: Add check for close-on-exec flag

[Xiao Yang]

pidfd_open(2) will set close-on-exec flag on the file descriptor as it
manpage states, so check close-on-exec flag by fcntl(2).

Also avoid compiler warning by replacing (long) TST_RET with (int) pidfd:
------------------------------------------------------
In file included from pidfd_open01.c:9:
pidfd_open01.c: In function ‘run’:
../../../../include/tst_test.h:76:41: warning: format ‘%i’ expects argument of type ‘int’, but argument 5 has type ‘long int’ [-Wformat=]
   76 |   tst_brk_(__FILE__, __LINE__, (ttype), (arg_fmt), ##__VA_ARGS__);\
      |                                         ^~~~~~~~~
../../../../include/tst_safe_macros.h:224:5: note: in expansion of macro ‘tst_brk’
  224 |     tst_brk(TBROK | TERRNO,                          \
      |     ^~~~~~~
pidfd_open01.c:20:9: note: in expansion of macro ‘SAFE_FCNTL’
   20 |  flag = SAFE_FCNTL(TST_RET, F_GETFD);
------------------------------------------------------

Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
---
 .../kernel/syscalls/pidfd_open/pidfd_open01.c  | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/testcases/kernel/syscalls/pidfd_open/pidfd_open01.c b/testcases/kernel/syscalls/pidfd_open/pidfd_open01.c
index 93bb86687..293e93b63 100644
--- a/testcases/kernel/syscalls/pidfd_open/pidfd_open01.c
+++ b/testcases/kernel/syscalls/pidfd_open/pidfd_open01.c
@@ -6,17 +6,27 @@
  * Basic pidfd_open() test, fetches the PID of the current process and tries to
  * get its file descriptor.
  */
+
+#include <sys/types.h>
+#include <unistd.h>
+#include <fcntl.h>
 #include "tst_test.h"
 #include "lapi/pidfd_open.h"
 
 static void run(void)
 {
-	TEST(pidfd_open(getpid(), 0));
+	int pidfd = 0, flag = 0;
+
+	pidfd = pidfd_open(getpid(), 0);
+	if (pidfd == -1)
+		tst_brk(TFAIL | TERRNO, "pidfd_open(getpid(), 0) failed");
+
+	flag = SAFE_FCNTL(pidfd, F_GETFD);
 
-	if (TST_RET == -1)
-		tst_brk(TFAIL | TTERRNO, "pidfd_open(getpid(), 0) failed");
+	SAFE_CLOSE(pidfd);
 
-	SAFE_CLOSE(TST_RET);
+	if (!(flag & FD_CLOEXEC))
+		tst_brk(TFAIL, "pidfd_open(getpid(), 0) didn't set close-on-exec flag");
 
 	tst_res(TPASS, "pidfd_open(getpid(), 0) passed");
 }
-- 
2.21.0